Appearance and internal soundness
Appearance
The internal and external surface finish of the tubes shall be typical of the manufacturing process and,
where applicable, the heat treatment, and it shall be such that any surface imperfections such as ridges, dents or
shallow grooves requiring dressing can be identified.
Option 3: A surface condition suitable for special further processing is specified by the purchaser.
Any surface imperfections, whose depth cannot be clearly identified (i.e. scales, overlaps) shall be
dressed in accordance with 8.4.1.3 or treated in accordance with 8.4.1.4.
It shall be permissible to dress, only by grinding or machining, surface imperfections provided that,
after doing so, the dimensions are within the specified tolerances. All dressed areas shall blend smoothly into the
contour of the tube.
Surface imperfections which encroach on the specified minimum wall thickness shall be considered
defects and tubes containing these shall be deemed not to conform to this Part of EN 10305.
8.4.1.5 The tubes shall have smooth outer and inner surfaces. The roughness Ra shall be :
¾ £ 4 μm on the outer surface of tubes in the delivery conditions +SR, +A and +N ;
¾ £ 4 μm on the outer and inner surface of tubes in the delivery conditions +C and +LC.
Verification of surface roughness and/or lower roughness values may be specified (see options 4 and 5).
NOTE In the case of the inner surface this requirement applies to inner diameters ³ 15 mm.
